TORONTO, April 18 (Reuters) - A Canadian man accused of helping 14 people in the province of Ontario kill themselves by selling a legal but deadly substance online will avoid a murder trial by pleading guilty to lesser charges, his lawyer said on Saturday.

Kenneth Law, 60, will plead guilty to counseling or aiding suicide under a deal with Crown prosecutors that will see more serious first-degree murder charges withdrawn, Matthew Gourlay of Henein Hutchison Robitaille said in an email.

Law's case is scheduled to return to court in Newmarket, Ontario, north of Toronto, on Monday. His plea will be entered at a later date, Gourlay said. 

Gourlay declined further comment. Ontario's Ministry of the Attorney General didn't immediately respond to a request for comment.

Law is facing 14 counts of first-degree murder and 14 counts of counseling or aiding suicide related to 14 victims, all Ontario residents between the ages of 16 and 36 who died by suicide. 

Canadian police allege Law, a former cook at a Toronto hotel, operated several websites starting around 2020 through which he marketed and sold a toxic salt and other items, including masks and hoods, that could be used for self-harm.

Canadian investigators allege that Law mailed at least 1,200 packages to addresses in more than 40 countries, including around 160 in Canada.

The alleged shipments prompted authorities in several countries to examine whether the products were responsible for deaths in their jurisdictions and to conduct welfare checks on those who purchased them.

A spokesperson for Britain's National Crime Agency said in a statement in April it is investigating potential crimes linked to the deaths of 112 people who purchased items to assist with suicide from Canada-based websites.

"Our investigation explores all viable leads linked to these websites and a Canadian suspect in order to identify evidence of crimes committed in the UK," the spokesperson said, without naming the suspect.

Law has been in custody since being arrested at his home west of Toronto in May 2023.

A conviction for counseling or aiding suicide comes with a prison sentence of up to 14 years, according to Canada's Criminal Code. First-degree murder in Canada carries a mandatory sentence of life imprisonment with no chance of parole for a minimum of 25 years.

(Reporting by Ryan Patrick Jones; Editing by Sergio Non and Chizu Nomiyama )

By Ryan Patrick Jones